The present invention relates to railway vehicles and more particularly to a device adapted to apply on the body of the vehicle a force for tilting the body about a longitudinal axis, or a force compensating for the centrifugal and centripetal forces acting on the vehicle in a curve, of the type comprising at least one force-applying hydraulic cylinder device and elements for detecting and calculating the force to be applied.
It will be recalled that the tilt of the vehicle body about an axis which is longitudinal or parallel to the track is a means employed on certain passenger railway vehicles for reducing the discomfort of the passengers resulting from the fact that the vehicle travels through the curves at a speed which is higher--and sometimes lower--than the equilibrium speed corresponding to the natural cant of the track. Depending on whether the vehicles travel through the curve above or below the equilibrium speed, the passengers are exposed to accelerations which are, relative to the floor of the car, respectively centrifugal or centripetal, this being all the more true because cars which have no body tilting equipment and a conventional suspension in a low bearing plane, tilt in the wrong direction (they lean toward the exterior of the curve when the speed is higher than the equilibrium speed and lean toward the interior of the curve in the opposite case).
Disregarding the passive systems whose suspension plane is higher than the center of gravity of the body and whose performances are poor owing to the inertias involved and to the relatively weak return action of the forces of gravity, a certain number of studies, and even constructions, exist which are based on active devices whose purpose is to return the body to a set position more rapidly than the aforementioned passive systems.
To the set position corresponds an apparent gravity force (resulting from the gravity force of the earth and the centrifugal acceleration force due to the curve) whose component parallel to the floor of the car is, in certain cases, nil and, in other cases, has a limited value; to minimize the effect on the passenger of transverse accelerations parallel to the floor of the vehicle, that constitutes a spatial reference for the passenger placed inside the vehicle.
The commercial interest of the body tilt is to improve the comfort of the passenger for given speeds in curves or, for a given comfort, increase the speed in the curves.